How To Succeed At Online Dating: Try An Expansive Pose : Shots - Health NewsHow people sit or where their arms and legs are in the images they share loom large in potential daters' calculations, according to experiments involving speed dating and an online dating app.

If you're young and single, chances are you're rejecting potential dates left and right on apps like Tinder, Bumble and OkCupid.

It's a brutal virtual world. Hundreds of people are whittled down to a few in minutes. In the seconds you lingered on one person's profile, four pictures and an ambiguous job title, what made you swipe him or her to the right?

First impressions count in ways you might not expect. How people sit or where their arms and legs are in the images they share seem to loom large in potential daters' calculations, according to experiments involving speed dating and an online dating app.

The Body Language Of Online Dating

One of the guys in the study displays an expansive body posture (left) that led to a better dating response than the contracted posture, a real downer.

Source: PNAS

Credit: Vacharkulksemsuk et al.

In these experiments, the researchers compared young adults' closed, slouched postures against open, or expanded, ones.

"An expansive, open posture involves widespread limbs, a stretched torso and general enlargement of occupied space," says Tanya Vacharkulksemsuk, a social psychologist at the University of California, Berkeley and lead author on the study published Monday in the Proceedings of the National Academy of Sciences.

For the 144 speed daters, Vacharkulksemsuk says, "expansiveness nearly doubles chances of getting a yes [to see each other again.]"

Separately, she and her colleagues had three men and three women create two dating profiles each on a popular dating app. (All six participants were white and heterosexual). Their profiles were identical in every way except the pictures in one profile were all expanded postures, while its twin had all contracted poses.

The participants swiped yes on every potential suitor — 3,000 in total — for 48 hours. "Profiles that feature expansive photos were 27 percent more likely to get a yes," Vacharkulksemsuk says. Expanding made both men and women more desirable during speed dating and in the dating app. The effect was more pronounced for men, however.

These postures convey power and openness, says Vacharkulksemsuk. "The information packing in that nonverbal behavior is social dominance, and where that person stands in a hierarchy," she says. And, presumably, the person high in the pecking order is sexy. Alphas are scarce and in demand.

On the other hand, Alpha Boy could be a cocky jerk. "Not everyone is going to go for someone showing an expansive posture," says Jessica Tracy, a social psychologist at the University of British Columbia who didn't work on the study." We have evidence that sometimes these kinds of open displays lead to problems. It can look arrogant."

Over-expanding can backfire. Think manspreading, for example, when the guy next to you on the bus or subway pushes a leg into your space to give himself a little more air. A display like that may go over as poorly on Tinder as it does on public transportation, where it is most, um, widespread.

But, in general, expansive postures are more attractive, Tracy says. "We know these displays communicate high status and rank. And it is adaptive from a purely financial perspective to mate or marry or whatever a woman who does have high rank, right?"

Often, you can see also somebody's alma mater and job title. But Joel Wade, a social psychologist at Bucknell University who wasn't involved with the work, says these nonverbal signals might trump other info. "I should say we are ingrained, wired, biologically predisposed to notice these behaviors," he says "The proverbial behavior doesn't lie. Maybe [we think] the picture shows more credibility."

With the scant information available to people making online dating decisions, Vacharkulksemsuk thinks those deep biological predispositions become very influential. "The most exciting, coolest [part of] these results are capturing something very special about what dating looks like in the current day," she says. "This is just that initial first step. How do I even get that first date?"

But posturing and gesturing isn't all that makes someone desirable. And if you've ever stretched out your arms for a hug and gotten a handshake, you know that sometimes expanding doesn't always help.

Shots is the online channel for health stories from the NPR Science Desk. We report on news that can make a difference for your health and show how policy shapes our health choices. Look to Shots for the latest on research and medical treatments, as well as the business side of health. Your hosts are Scott Hensley and Nancy Shute. You can reach the Shots team via our contact form.